/*
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF licenses this file to You under the Apache License, Version 2.0
 * (the "License"); you may not use this file except in compliance with
 * the License.  You may obtain a copy of the License at
 * 
 *      http://www.apache.org/licenses/LICENSE-2.0
 * 
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
package net.phoenix.repository.query.jql;

import javax.jcr.query.InvalidQueryException;
import javax.jcr.query.qom.Column;

import antlr.collections.AST;

/**
 * Jigsaw server
 * 
//## selectClause:
//##     SELECT DISTINCT? selectedPropertiesList | ( NEW className OPEN selectedPropertiesList CLOSE );

selectClause
	: SELECT^	// NOTE: The '^' after a token causes the corresponding AST node to be the root of the sub-tree.
		{ weakKeywords(); }	// Weak keywords can appear immediately after a SELECT token.
		(DISTINCT)? ( selectedPropertiesList | newExpression | selectObject )
	;
selectedPropertiesList
	: aliasedExpression ( COMMA! aliasedExpression )*
	;
aliasedExpression
	: expression ( AS^ identifier )?
	;
 * @author    <a href="shamphone@gmail.com">Li XiongFeng</a>
 * @date      2012-4-22
 * @version   1.0.0
 */
public class SelectClauseAST extends JQLBaseAST{

	private Column[] columns = null;
	/**
	 * 
	 */
	private static final long serialVersionUID = 2676774581503254006L;
	public Column[] getColumns(){
		if(this.columns!=null)
			return this.columns;
		this.columns=new Column[this.getNumberOfChildren()];
		AST child = this.getFirstChild();
		int count = 0;
		while(child!=null){
			columns[count++]= (Column)child;
			child = child.getNextSibling();
		}
		return columns;
	}
	@Override
	public String toJQL() {
		StringBuffer buffer= new StringBuffer("");
		JQLBaseAST child = (JQLBaseAST)this.getFirstChild();
		while(child!=null){
			if(buffer.length()>0)
				buffer.append(",");
			buffer.append(child.toJQL());
			child = (JQLBaseAST)child.getNextSibling();
		}
		buffer.insert(0, "SELECT ");
		return buffer.toString();
	}
	/* (non-Javadoc)
	 * @see net.phoenix.repository.query.parser.JQLBaseAST#generateSQL(net.phoenix.repository.query.parser.JQLQuery)
	 */
	@Override
	public void generateSQL(JQL2SQL collector) throws InvalidQueryException{
		StringBuffer buffer= new StringBuffer("");
		JQLBaseAST child = (JQLBaseAST)this.getFirstChild();
		while(child!=null){
			((JQLColumnAST)child).generateColumnSQL(collector);
			if(buffer.length()>0)
				buffer.append(",");
			buffer.append(collector.pop());
			child = (JQLBaseAST)child.getNextSibling();
		}
		buffer.insert(0, "SELECT ");
		collector.push(buffer.toString());
	}
	
	
}
